Two metals `(A)` and `(B)` belong to the same group of the periodic table. Metal `(A)` forms and insoluble oxide but a soluble sulphate, metal `(B)` forms a soluble oxide but an insoluble oxide but an insoluble sulphate. Both metals `(A)` and `(B)` form hydroxides which are soluble in alkalis. `(A)` and `(B)` are

Options

A. `Ba` and `Mg`
B. `Na` and `K`
C. `Mg` and `Ba`
D. `K` and `Rb`

Answer

C

Explanation

`MgO` is insoluble, whereas `MgSO_(4)` is soluble, whereas `BaO` is soluble, but `BaSO_(4)` is insoluble.